<!--
 * @Description: 
 * @Author: chenju
 * @Date: 2021-10-13 16:01:00
 * @LastEditors: qingyang
 * @LastEditTime: 2022-01-20 17:30:09
-->
<template>
  <transition v-on="on">
    <slot></slot>
  </transition>
</template>
<script lang="ts">
import { defineComponent } from 'vue';
import { addClass, removeClass } from '@/utils/domUtils';

export default defineComponent({
  name: 'CCollapseTransition',
  setup() {
    return {
      on: {
        beforeEnter(el: any) {
          addClass(el, 'collapse-transition');
          if (!el.dataset) el.dataset = {};

          el.dataset.oldPaddingTop = el.style.paddingTop;
          el.dataset.oldPaddingBottom = el.style.paddingBottom;

          el.style.height = '0';
          el.style.paddingTop = 0;
          el.style.paddingBottom = 0;
        },

        enter(el: any) {
          el.dataset.oldOverflow = el.style.overflow;
          if (el.scrollHeight !== 0) {
            el.style.height = el.scrollHeight + 'px';
            el.style.paddingTop = el.dataset.oldPaddingTop;
            el.style.paddingBottom = el.dataset.oldPaddingBottom;
          } else {
            el.style.height = '';
            el.style.paddingTop = el.dataset.oldPaddingTop;
            el.style.paddingBottom = el.dataset.oldPaddingBottom;
          }

          el.style.overflow = 'hidden';
        },

        afterEnter(el: any) {
          // for safari: remove class then reset height is necessary
          removeClass(el, 'collapse-transition');
          el.style.height = '';
          el.style.overflow = el.dataset.oldOverflow;
        },

        beforeLeave(el: any) {
          if (!el.dataset) el.dataset = {};
          el.dataset.oldPaddingTop = el.style.paddingTop;
          el.dataset.oldPaddingBottom = el.style.paddingBottom;
          el.dataset.oldOverflow = el.style.overflow;

          el.style.height = el.scrollHeight + 'px';
          el.style.overflow = 'hidden';
        },

        leave(el: any) {
          if (el.scrollHeight !== 0) {
            // for safari: add class after set height, or it will jump to zero height suddenly, weired
            addClass(el, 'collapse-transition');
            // fix #968 collapse animation failure.
            // in vue3.0.4, transitionProperty is set 'none' to avoid 'v-leave-from' issue
            el.style.transitionProperty = 'height';
            el.style.height = 0;
            el.style.paddingTop = 0;
            el.style.paddingBottom = 0;
          }
        },

        afterLeave(el: any) {
          removeClass(el, 'collapse-transition');
          el.style.height = '';
          el.style.overflow = el.dataset.oldOverflow;
          el.style.paddingTop = el.dataset.oldPaddingTop;
          el.style.paddingBottom = el.dataset.oldPaddingBottom;
        }
      }
    };
  }
});
</script>
<style lang="scss" scoped>
.collapse-transition {
  transition: 0.2s height ease-in-out, 0.2s padding-top ease-in-out, 0.2s padding-bottom ease-in-out;
}
.horizontal-collapse-transition {
  transition: 0.2s width ease-in-out, 0.2s padding-left ease-in-out, 0.2s padding-right ease-in-out;
}
</style>
